There has been proposed a technology for protecting an electric motor controller on an electric vehicle at the time of vehicle collision {U.S. Patent Application Publication No. 2010/0283337 (hereinafter referred to as “US 2010/0283337 A1”)}. According to US 2010/0283337 A1, an objection thereof is to provide a vehicle drive apparatus which appropriately protects a power control unit against an external impact thereon (see Abstract and paragraph [0008]).
In order to achieve the above object, the vehicle drive apparatus, denoted by 20, according to US 2010/0283337 A1 includes motor generators MG1, MG2 for generating driving forces and a power control unit (PCU) 21 integrally combined with the motor generators MG1, MG2 for controlling the motor generators MG1, MG2 (see paragraph [0027]). The PCU 21 includes a low-voltage circuit section 71 to which a relatively low voltage is applied, a high-voltage circuit section 75 disposed at a rear side of the vehicle relative to the low-voltage circuit section 71 and to which a relatively high voltage is applied, and a cooling plate 72 for cooling the high-voltage circuit section 75, the cooling plate 72 being disposed between the low-voltage circuit section 71 and the high-voltage circuit section 75 in the longitudinal direction of the vehicle (see Abstract, paragraphs [0055], [0057] through [0059], and FIG. 4).
According to US 2010/0283337 A1, when the vehicle drive apparatus 20 is subjected to an impact from the front end of the vehicle, the low-voltage circuit section 71 absorbs the impact, and the cooling plate 72 that serves to increase the mechanical strength of the front side of the high-voltage circuit section 75 buffers the impact which reaches the high-voltage circuit section 75 to which a high voltage is applied, thereby protecting the PCU 21 from the impact appropriately (see paragraphs [0010] and [0064]). On the rear side of the high-voltage circuit section 75, a water jacket 74, a portion of an MG2/inverter case 64 (a right wall of the water jacket 74 in FIG. 4), and the motor generator MG2 are disposed (see FIGS. 4 through 6).